The present invention relates to a buckle for swimming/diving goggles and, more particularly, to a buckle for swimming/diving goggles allowing easy adjustment of a length of a head strap while providing stable operation.
Swimming goggles generally include two lenses, two frames, a bridge, a buckle, and a head strap. The buckle allows adjustment of a length of the head strap. FIG. 10 shows a conventional buckle 1′ including an end with an engagement portion 11′ for engagement with a body 3′ of a pair of swimming goggles. The other end of the buckle 1′ includes a coupling portion 12′ for coupling with a soft head strap 2′. The coupling portion 12′ includes pegs 121′ and 122′ at an intermediate portion thereof. A notch 123′ is defined in a front end of the coupling portion 12′. The head strap 2′ is extended between the notch 123′ and the peg 121′ and wound around the pegs 121′ and 122′ and extended between the notch 123′ and the peg 121′ again, fixing the head strap 2′. When adjustment of the head strap 2′ is required, the user removes the body 3′ from his or her head, loosens the head strap 2′, and adjusts the length of the head strap 2′, which is troublesome and time-consuming. However, the length of the head strap 2′ after adjustment may not fit the head of the user. As a result, readjustment of the head strap 2′ is required when the head strap 2′ is either too tight or too loose. Furthermore, the head strap 2′ deforms significantly at the bends wound around the pegs 121′ and 122′.
U.S. Pat. No. 6,832,394 discloses swimming goggles including a resilient button that can be pressed to control adjustment of a length of the head strap. However, the resilient button is pressed in a direction against the head, causing discomfort to the user.
U.S. Pat. No. 7,020,905 discloses a swimming goggle including head fasteners respectively connected with left and right frames and adjusting apparatuses for adjusting the head fasteners. Each adjusting apparatus includes a base, a cover, a biasing arm, two operating buttons, and a flexible arcuate plate. A shaft is received in a shaft hole of the base. In assembly, the head fastener is pulled from an inlet of the base, around the shaft, and out of an outlet of the base. The biasing arm, the operating buttons, and the arcuate plate are assembled together. The biasing arm has a biasing end for cooperating with the shaft to engage with a stop slot of a corresponding head fastener. The arcuate plate has an end connecting with sides of the operating buttons. The opposite end of the arcuate plate connects with an end of the biasing arm opposite to the biasing end for providing return force. The operating buttons are assembled in grooves of the cover and have ends projecting slightly beyond the sides of the cover for convenient performance. The basing end of the biasing arm engages with the stop slot of a corresponding head fastener such that the head fastener can not move toward the inlet, but can only move out of the outlet. The operating buttons can be pressed to cause an unlocking block of each operating button to move the biasing end of the biasing arm so as to disengage the biasing arm from the stop slot. The head fasteners are, thus, free to allow adjustment. The operating buttons are pressed in a direction without causing discomfort to the head of the user. However, the biasing arm, the arcuate plate, and the buttons are integrally formed such that deformation of the arcuate plate would not be easy if the arcuate plate is made of a rigid material. On the hand, the arcuate plate can deform easily when the operating buttons are pressed if the arcuate plate is made of a soft material. However, the soft arcuate plate can not reliably retain the basing end of the biasing arm in the stop slot of the head fastener. Furthermore, the arcuate plate provides the returning force for only side of the corresponding operating button, and the other side of the operating button is not supported. The returning forces after releasing the operating buttons are not even, failing to provide stable operation.